New emissions mandates are reshaping the maritime industry. Here’s what to know about the evolving rules—and how operators are adapting.
Regulations targeting maritime emissions are accelerating around the world. From international climate mandates to aggressive local air quality rules, the pressure is rising for shipping companies to cut pollution both at sea and in port.
This urgency reflects the scale of the challenge: maritime shipping moves over 80% of global trade and, in the process, contributes nearly 3% of total greenhouse gas (GHG) emissions. At the same time, vessels release high volumes of sulfur oxides (SOₓ), nitrogen oxides (NOₓ), and particulate matter (PM). These pollutants harm the air quality and public health of frontline port communities around the world.
Companies operating in the industry that plan ahead won’t just avoid compliance and regulatory issues, but they’ll stand to build more resilient operations that will offer real business benefits. For operators, port authorities, and logistics stakeholders, understanding the scope of maritime emissions regulations today, and what could come tomorrow, is the first step toward a future-ready strategy.
Why maritime emissions are a regulatory priority
Maritime emissions are facing increasing scrutiny due to their outsized impact on both global climate and local air quality.
These emissions come from multiple sources across vessel operations. The largest contributors include:
• Main and auxiliary engines, which burn bunker fuel while ships are underway or idling in port
• Boilers and onboard power systems, especially active during cargo handling
• Fuel storage and transfer systems, which can leak or vent harmful vapors
From these activities, ships release a complex mix of pollutants. Each plays a role in environmental damage and human health risks:
Carbon dioxide (CO₂)
The primary GHG driving global climate change.
Nitrogen oxides (NOₓ)
Pollutants that contribute to primary GHGground-level ozone and smog, leading to respiratory problems.
Sulfur oxides (SOₓ)
Compounds that react in the atmosphere to form fine particles, harming air quality and causing acid rain that primary GHGground-level ozone and smogendangers aquatic species.
Particulate matter (PM)
Microscopic particles (dust, dirt, soot, smoke, etc., which can be made up of hundreds of different chemicals) that penetrate deep into the lungs and bloodstream, causing long-term health effects, are also called particle pollution.
Around the world, prolonged exposure to ship emissions has been linked to higher rates of asthma, lung disease, and cardiovascular conditions. The most severe health impacts are concentrated in coastal and port communities, where populations are regularly exposed to high concentrations of air pollutants. Environmentally, these pollutants accelerate climate change, damage coastal ecosystems, and contribute to ocean acidification
These pressures are driving a rapid policy shift, and operators must act now to keep pace.
Breaking down the regulatory landscape for maritime emissions
The rules governing maritime emissions span from international treaties to local enforcement. To understand which regulations apply to your fleet or operations, start by identifying where your vessels sail, what types of ships you operate, and which ports you call on regularly.
Below is a simplified guide to the major regulatory efforts shaping the future of maritime emissions control:
Global frameworks
The International Maritime Organization (IMO) is the UN body that oversees global shipping standards. Through the MARPOL convention (formally known as the International Convention for the Prevention of Pollution from Ships), the IMO sets international rules for emissions, fuel quality, and vessel efficiency.
IMO GHG Strategy
This climate plan targets a 20-30% reduction in total shipping emissions by 2030, and full net-zero emissions by 2050. It’s a global push toward cleaner fuels and smarter operations.
MARPOL Annex VI
This foundational regulation limits air pollutants from ships and establishes Emission Control Areas (ECAs) where stricter standards apply. It also underpins newer efficiency measures, including:
EEXI (Energy Efficiency Existing Ship Index)
A one-time certification evaluating the design efficiency of existing ships. Required for compliance under IMO regulations.
CII (Carbon Intensity Indicator)
An annual measure of a vessel’s carbon emissions per unit of cargo and distance traveled. Affects a ship’s operational rating and must improve year over year to remain compliant.
Major regional regulations
While the IMO sets the global baseline, many regions have stepped up with assertive local policies.
California Air Resources Board (CARB)
CARB enforces some of the world’s strictest air quality rules for vessels entering California waters. The 2020 At-Berth regulation requires ocean-going vessels docked at California’s busiest ports to plug into shore power or use emissions control technology. By 2027, it is estimated that this rule will deliver a 90% reduction in pollution.
European Union Emissions Trading Scheme (EU ETS)
As of 2024, the EU began applying its EU ETS to maritime shipping. This means that large ship operators need to purchase allowances based on their CO₂ output, much like factories and power plants already do. It’s a financial incentive to cut emissions fast.
United Kingdom (UK ETS and Maritime Decarbonisation Strategy)
From 2026, the UK will require ship operators to purchase emissions allowances under the UK ETS, aligning with similar EU measures. In parallel, the UK Government has launched a comprehensive Maritime Decarbonisation Strategy, targeting a 30% reduction in lifecycle GHG emissions from domestic maritime by 2030 (relative to 2008), rising to 80% by 2040 and net-zero by 2050. The strategy includes a proposed requirement for zero or near-zero emissions from vessels at berth, supported by a call for evidence on Net Zero Ports.
Significant investment is also being channelled into zero-emission vessels and green port infrastructure through initiatives like the Clean Maritime Demonstration Competition, which is supporting STAX’s PortZero initiative to demonstrate carbon and air pollution capture from berthed vessels.
China’s Domestic Emission Control Areas (DECAs)
China has established DECAs in major port regions. These require the use of 0.5% sulfur fuel within 12 nautical miles and 0.1% sulfur fuel at berth in key ports. A national carbon trading scheme for shipping is also being considered.
Singapore’s Decarbonization Blueprint
Singapore is not yet part of an ECA (Emission Control Area) but is a global leader in decarbonization research and development. This roadmap seeks to achieve net-zero emissions for Singapore’s port terminals by 2050.
In response to these evolving regulatory demands, operators are rethinking how ships are fueled, equipped, and run—adopting new strategies to stay compliant and competitive.
How the industry is meeting evolving regulatory requirements
As regulations become more stringent and widespread, the maritime industry is undergoing a fundamental shift in how operations are designed and managed. Achieving compliance means making smart decisions across fuel systems, onboard technologies, and day-to-day operations.
Here’s how operators are rising to the challenge:
Alternative fuels
To cut emissions at the source, many shipping companies are transitioning away from traditional bunker fuels toward cleaner alternatives. Each fuel type comes with trade-offs in emissions, availability, and safety.
- Liquefied Natural Gas (LNG): Widely adopted but still emits methane, a potent GHG.
- Methanol: Produces lower emissions and is easier to handle than LNG. It can be made from renewable sources, though its most current supply comes from fossil fuels.
- Ammonia and hydrogen: Zero-emission fuels but face scalability and safety hurdles.
Exhaust treatment technologies
When cleaner fuels aren’t an option, or to add a layer of compliance, many vessels are installing systems that treat emissions before they’re released.
- Scrubbers: These technologies remove sulfur oxides from exhaust gases. Open-loop scrubbers discharge wastewater into the ocean, while closed-loop systems treat and reuse it onboard.
- Carbon capture systems: These systems aim to trap CO₂ emissions onboard before they escape into the atmosphere.
Operational efficiencies
Operators are also turning to smarter practices that cut emissions without requiring major equipment changes.
- Slow steaming: By simply reducing vessel speed, this technique cuts fuel use and emissions.
- Route optimization software: Minimizes unnecessary engine hours.
Shore power and cold ironing
Shore power, also known as cold ironing, is the process of connecting a ship to land-based power grids while docked. This allows vessels to shut off their diesel generators and continue running onboard systems without producing emissions during port stays. However, shore power has limitations: it requires significant infrastructure investment at ports, compatible onboard equipment, and a stable power grid. Additionally, it only reduces emissions while the vessel is docked, and does not eliminate emissions from boilers.
Emissions capture and control solutions
Emissions capture and control systems are technologies that trap and treat engine exhaust in real time, filtering harmful pollutants before they’re released into the environment. Unlike shore power, these systems operate independently of the power grid. Solutions like STAX connect directly to a vessel’s exhaust stack, helping operators meet regulatory requirements without costly retrofits or schedule disruptions.
While many solutions are still evolving—with limitations around cost, infrastructure, or readiness—emissions capture and control technologies offer an immediate path to compliance. STAX reduces emissions today, bridging the gap to a clean-air future as the industry transitions to more sustainable fuel alternatives.
Navigating the regulatory future of the shipping industry
Compliance is fast becoming a non-negotiable aspect of shipping operations. For port authorities, vessel owners, and operators, the opportunity lies in embracing solutions that enable sustainable operations, without compromising productivity or uptime.
STAX helps ports and carriers navigate this regulatory complexity through turnkey emissions capture systems, built to meet today’s toughest requirements and tomorrow’s evolving standards.
Help your team achieve emissions compliance efficiently and effectively. Learn more about STAX’s technology.
